Diverter flow line seal

ABSTRACT

A diverter body having an upper portion, a central portion and a lower portion is secured to the upper end of a riser and lands in a housing. The central portion has lateral flow openings that axially align with a lateral flowline outlet in the housing. A pair of identical gallery seals locate above and below the lateral flowline outlet. The upper gallery seal is located between the upper portion, the central portion and the housing. The upper gallery seal has upper and lower metal rings and a central elastomer sandwiched therebetween. An outer diameter of the elastomer seals against the housing bore. The rings are symmetric and are mated to the elastomer along interfaces which are S-shaped in cross-section to form shoulders. The shoulders face radially inward. An annular cavity and a pair of flexible annular lips are formed along the inner diameter portion of the elastomer. A passage extends through the diverter bodies and communicates with the cavity. Hydraulic fluid is pumped through the passages to pressurize the cavities and energize the elastomers, forcing the outer diameter portions of the elastomers outward to seal against the bore.

TECHNICAL FIELD

This invention relates in general to diverters and in particular to adiverter flowline seal.

BACKGROUND ART

Diverters are mounted to offshore drilling rigs below the rig floor foruse in early stages of drilling. A support housing mounts below the rigfloor and has a lateral flowline outlet for directing mud flow when thediverter is closed. The housing is a tubular member with an axial bore.A diverter body is secured to the upper end of a riser, is loweredthrough the rotary table and lands in the housing. The diverter body haslateral flow openings that are axially aligned with the lateral flowlineoutlet. A pair of seals are located above and below the lateral flowlineoutlet.

The seals seal the diverter body to the diverter housing. One type ofprior art seal comprises a bulk seal having cylindrical inner and outerdiameter walls. The bulk seal is bonded to upper and lower metal rings.After the diverter body lands, hydraulic pressure is applied to theinner diameter of each of the seals to deform the elastomer into sealingengagement with the diverter housing. While workable, improvements aredesired.

DISCLOSURE OF INVENTION

A diverter body having an upper portion, a central portion and a lowerportion is secured to the upper end of a riser, lowered through therotary table and lands in a diverter housing. The central portion haslateral flow openings that axially align with a lateral flowline outletin the housing. A pair of identical gallery seals locate above and belowthe lateral flowline outlet.

The upper gallery seal is located between the upper portion, the centralportion and the housing. The upper gallery seal has upper and lowermetal rings and a central elastomer sandwiched therebetween. An innerdiameter of the elastomer seals against the central body, and an outerdiameter of the elastomer seals against the housing bore. The metalrings are symmetrical and are bonded to the elastomer along interfaceswhich are S-shaped in cross-section to form shoulders. The shouldersface generally radially inward. The outer diameter portions of the ringshave greater axial dimensions than their corresponding inner diameterportions.

An annular cavity and a pair of flexible annular lips are formed alongthe inner diameter portion of the elastomer. A hydraulic passage extendsthrough the upper portion and the central portion, and communicates withthe cavity. After installation, the lips deform and seal against thecentral portion. After the diverter body lands in the housing, hydraulicfluid is pumped through the passages to pressurize the cavities andenergize the elastomers, forcing the outer diameter portions of theelastomers outward to seal against the housing bore. The seals preventflowing mud from escaping between the diverter and the housing.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a diverter having flow line sealsconstructed in accordance with the invention.

FIG. 2 is an enlarged, partial sectional view of one of the flow lineseals of the diverter of FIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, a low pressure blowout preventer or diverter 11 ismounted to a drilling rig below the rig floor. Diverter 11 includes asupport housing 13 mounted to the rig floor. Support housing 13 has alateral flowline outlet 15 for directing mud flow when diverter 11 isclosed. Housing 13 is a tubular member having an axial bore 14. Adiverter body 21 is secured to the upper end of a riser and lands inhousing 13. Diverter body 21 has an upper portion 23, a central portion25 and a lower portion 27, which are secured to one another with bolts29. Central portion 25 has lateral flow openings 30 that are axiallyaligned with lateral flowline outlet 15. A circumferential recess 28 islocated on the outer diameter of body 25 to communicate the flow fromopenings 30 to outlets 15.

A pair of identical gallery seals 31 locate above and below lateralflowline outlet 15 in rectangular annular recesses 32, 34. Upper galleryseal 31 is located between upper portion 23, central portion 25 andhousing 13. Lower gallery seal 31 is located between lower portion 27,central portion 25 and housing 13. Referring to FIG. 2, upper galleryseal 31 comprises upper and lower metal rings 33, 35, and a centralelastomer 37 sandwiched therebetween. Inner diameter 41 seals againstcentral body 25, and outer diameter 43 of seal 31 seals against housingbore 14. Rings 33, 35 are symmetric and may be directly bonded toelastomer 37 along nonrectilinear interfaces 45, 47, respectively. Inthe preferred embodiment, nonrectilinear interfaces 45, 47 are S-shapedin cross-section to form shoulders 49 with rounded corners. Shoulders 49face radially inward. The outer diameter portions 43 of rings 33, 35have greater axial dimensions than their corresponding inner diameterportions 41. Conversely, the inner diameter portion 41 of elastomer 37has a greater axial dimension than its outer diameter portion 43. Theouter diameter portions 43 of upper and central diverter bodies 23, 25,elastomer 37, and rings 33, 35 are closely spaced to bore 14 of housing13. When initially installed, these elements are flush with one another.

An annular cavity 51 and a pair of flexible annular lips 53 are formedalong the inner diameter portion 41 of elastomer 37. A hydraulic passage55 extends through upper portion 23 and central body 25, andcommunicates with cavity 51. Lips 53 protrude axially toward one anotherand abut the outer surface of central portion 25 along their innersides. Lips 53 also protrude radially inward to a diameter that is lessthan an outer diameter of body 25 prior to installation. A small annulus55 surrounds each lip 53. After installation, lips 53 deform and sealagainst body 25.

In operation, seals 31 are installed in diverter 11 with lips 53 sealingagainst body 25. Prior to installation, seal 31, which includeselastomer 37 and rings 33, 35, has an undeformed height or axialdimension that is greater than its deformed axial dimension. Inaddition, the undeformed outer diameter of elastomer 37 is flush withrings 33, 35. A clearance of up to one quarter inch may extend betweenthe outer diameter of elastomer 37 and housing bore 14. Diverter 11 islanded within housing 13 on a conduit (not shown). When seal 31 isdeformed, elastomer 37 is vertically compressed between rings 33, 35 sothat its outer diameter is squeezed outward to seal against bore 14 inthe clearance. Hydraulic fluid is then pumped through passages 55 topressurize cavities 51 and energize elastomer 37. Tensile shear stressescreated by the initial compression of elastomer 37 are reduced when itis energized by the hydraulic fluid. Because lips 53 seal against body25, increased hydraulic fluid pressure in cavity 51 causes the outerdiameter portions 43 of elastomer 37 to be forced outward to sealagainst bore 14 of body 13. Hydraulic fluid pressure is maintainedduring use. Seals 31 prevent the flowing mud from escaping betweendiverter 11 and housing 13.

The invention has several advantages. The lips provide a pressure sealto create an integral cavity for hydraulic fluid pressure. The lipseliminate a need for creating a hydraulic fluid pressure cavity withsecondary seals such as O-rings. The S-shaped interfaces allowsimultaneous energization of the lips and the elastomer against thebody. Integration of the inner and outer diameter seals eliminates theneed to establish a sealed bond along the S-shaped interfaces.

While the invention has been shown in only one of its forms, it shouldbe apparent to those skilled in the art that it is not so limited, butis susceptible to various changes without departing from the scope ofthe invention.

I claim:
 1. In a diverter having a housing having a bore, a body havingan axial passage and a lateral flow outlet extending from the axialpassage through the body and the housing, the improvement comprising:anannular upper seal located above the lateral flow outlet; an annularlower seal located below the lateral flow outlet; each of the sealshaving an elastomeric central portion with an inner diameter and anouter diameter; a hydraulic passage extending through the body forsupplying hydraulic fluid to the inner diameters of the central portionsto deform the outer diameters of the central portions outward intosealing engagement with the bore; a pair of metal rings abutting theupper and lower sides of the central portion of each of the seals; andeach of the rings having a generally inward-facing shoulder interfacewhich is matched to a mating shoulder interface on the central portionof each of the seals.
 2. The diverter of claim 1 wherein each centralportion comprises a pair of lips protruding from the inner diameter, thepair of lips being axially spaced apart to seal against the body to forma cavity for receiving the hydraulic fluid.
 3. The diverter of claim 1wherein each shoulder interface is generally S-shaped in cross-section.4. The diverter of claim 1 wherein each inner diameter of each of thecentral elastomeric portions has an axial dimension that is greater thanan axial dimension of the respective outer diameter of the centralelastomeric portion.
 5. A diverter, comprising:an outer stationaryhousing having a lateral flow outlet; an inner portion which landswithin the housing and which has a lateral passage that communicateswith the lateral flow outlet; a pair of gallery seals located betweenthe housing and the body, one of the seals being located above theoutlet of the housing, and the other of the seals being located belowthe outlet of the housing; and wherein each seal has an upper and alower metal ring and an elastomer located between the rings, theelastomer having an inner diameter and an outer diameter; and whereineach elastomer has upper and lower lips on the inner diameter which sealagainst the body and define a cavity; and a hydraulic passage in thebody for delivering hydraulic fluid to the cavity to force the outerdiameter into sealing engagement with the housing.
 6. The diverter ofclaim 5 wherein the lips protrude toward one another.
 7. The diverter ofclaim 5 wherein each elastomer interfaces with its respective ringsalong nonlinear surfaces.
 8. The diverter of claim 5 wherein eachelastomer interfaces with its respective rings along inner and outernonlinear surfaces, the axial distance between the rings at the innerdiameter of each of the elastomers being greater than the axial distancebetween the rings at the outer diameter.
 9. The diverter of claim 8wherein the nonlinear surfaces are S-shaped in cross-section.
 10. Thediverter of claim 5 wherein each elastomer is bonded to its, respectiverings.
 11. A seal for sealing between inner and outer members and havingan axis, comprising:a pair of metal rings; a central elastomer locatedbetween the metal rings, the elastomer having inner and outer sidewalls;each of the rings having a generally radially-facing shoulder interfacewhich is mated to the shoulder interface on the central portion; theelastomer having a pair of axially spaced-apart lips protruding from oneof the sidewalls into sealing engagement with one of the members,defining a cavity for receiving hydraulic fluid pressure to force theother of the sidewalls outward into sealing engagement with the other ofthe members.
 12. The seal of claim 11 wherein the axial distance betweenthe rings at said one of the sidewalls of the elastomer is greater thanthe axial distance between the rings at the said other of the sidewalls.